Sterilization of nitroparaffin-amine explosives

ABSTRACT

A PROCESS FOR STERILIZING AN AMINE SENSITIZED LIQUID EXPLOSIVE OF THE NITROPARAFFIN TYPE WHICH PROCESS COMPRISES ADDING TO THE SENSITIZED EXPLOSIVE A STERLIZING AGENT, FOR EXAMPLE, POLYCARBONATE, DIPHENYL ESTER OF CARBONIC ACID, FURALDEHYDE, 2,5-DIMETHYL 2,4-HEXADIENE, TRIBUTOXYBORINE, TRIBUTYLESTER OF PHOSPHORIC ACID, TETRAETHYLBOROSILICATE, BENZALDEHYDE, 1-PHENYL-1-PROPANONE, HEXANONE, SUCCINIC ANHYDRIDE, MALEIC ANHYDRIDE OR A COMBINATION THEREOF IN AN AMOUNT EFFECTIVE TO RENDER THE EXPLOSIVE NONDETONABLE.

United States Patent 3,746,588 ST'ERILIZATION 0F NITROPARAFFIN-AMINEEXPLOSIVES Nickolas Brunetz, La Mirada, and Robert A. Haskell,

Long Beach, Calili, assignors to Aerojet-General Corporation, El Monte,Calif. No Drawing. Filed Mar. 29, 1971, Ser. No. 129,245 Int. Cl. C06b7/00 U.S. Cl. 14989 2 Claims ABSTRACT OF THE DISCLOSURE A process forsterilizing an amine sensitized liquid explosive of the nitroparaffintype which process comp-rises adding to the sensitized explosive asterilizing agent, for example, polycarbonate, diphenyl ester ofcarbonic acid, furaldehyde, 2,5-dimethyl 2,4-hexadiene, tributoxyborine,tributylester of phosphoric acid, tetraethylborosilicate, benzaldehyde,1-phenyl-1-propanone, hexanone, succinic anhydride, maleic anhydride ora combination thereof in an amount effective to render the explosivenondetonable.

This invention relates to a method for rendering nondetonable sensitizedliquid explosive of the nitroparaflinamine type. In particular, thisinvention relates to sterilizing an explosive composition containingnitroparafiins sensitized with primary or secondary organic amines, orhydrazines.

Nitroparaflin explosive compositions find valuable application inquarrying where a powerful explosive having a high rate of detonation isrequired. The superior properties of the amine sensitized nitroparaflinexplosives make them useful in mining, for military purposes, in oilwell production and other applications where the use of explosives isnecessary. Liquid nitroparafiin explosives of the foregoing type aredescribed in U.S. Pats. 3,239,395 Lawrence, 3,132,060 Beegle et al.,2,967,099 Pool, and 2,690,964 Maisner. It will be appreciated that oncea nitroparaflin explosive has been sensitized with the amine, it must beexploded or otherwise it provides a dangerous disposal problem.

It has now been discovered that the addition of certain sterilizingagents to the sensitized nitroparaflin liquid explosive renders theexplosive inert and nondetonable. It has been established by test thatthe following materials or combinations thereof are efiective assterilizing agents for amine-sensitive nitroparaflin explosives:polycarbonate, diphenyl ester of carbonic acid, furaldehyde, 2,5-dimethyl 2,4 hexadiene, tributoxyborine, tributylester of phosphoricacid, tetraethylborosilicate, benzaldehyde, 1- phenyl-l-propanone,hexanone, succinc anhydride (2,5- diketotetrahydrofuran), and maleicanhydride 2,5-furanedione).

It is believed that the addition of the sterilizing agent reduces thenitroparafiin, destroys the amine salt earlier formed in the sensitizingreaction, produces water and other compounds including a semipolymer.The exact sterilizing reaction is not fully known. However, it is knownthat the sterilizing agent, polycarbonate for example, dissolvescompletely only in the sensitizer or the sensitized nitroparafiinliquid. It has been demonstrated that an amine saturated with thesterilizing agent is still capable of sensitizing a nitroparaffin fuelwhen added thereto; and, it is only after a period of time has lapsedthat the thus sensitized nitroparatfin explosive becomes inert andnondetonable. The time required to elfect sterilization, as described inthe preceding situation, is of approximately the same length of time asthat required in the more usual later addition of the sterilizing agentto the previously sensitized amine-hydrocarbon mixture. The sensitizedexplosive becomes inert in the last one percent of the sterilizationtime before completion of the sterilization reaction. Until then, theexplosive shows no substantial decreased output in energy and theexplosive may be detonated even though the sterilization has been addedsometime earlier.

Typically, the sterilizing agent is employed in an amount in the rangeof 4 to 15 percent by weight of the sensitized explosive. The speed withwhich the several sterilizers work varies considerably withdiphenylcarbonate being the fastest sterilizer. Polycarbonate is also aparticularly desirable material. The time parameter for sterilizationmay be altered somewhat by the concentration of the sterilizer employed,with an increase in concentration decreasing the time required to effectdesensitization or sterilization, which typically occurs within fiveminutes after the addition of the sterilizer. The sterilizerpolycarbonate, however, requires several (2-36) hours for its reactiondepending on the concentration of the polycarbonate, rod or resin and onthe temperature and concentration of the explosive. It is constantwithin the same system. Once sterilization is achieved, the reaction isirreversible and the explosive remains inert and cannot be detonated byany means of normal initiation. The timing of the sterilizing processmay be controlled by a timing capsule which has a controlled solutionrate seal. For example, polycarbonate seal will give a l0-24 hours delayof capsule opening, depending on the thickness of the seal.

Nitroparaflins utilizable in the process of present invention includeany of the liquid nitroparafiins, such as, nitromethane, dinitromethane,nitroethane, dinitroethane, nitro propane, nitrobutane, nitropentane,and nitrohexane including their many isomeric structures. The preferrednitroparafiin is mononitromethane, optionally containing up to 30percent by weight of nitroethane or nitropropane based on the weight ofthe nitromethane,

The sensitizer is typically a primary or secondary amine, e.g.,propylene diamine, ethylene diamine, diethylene triarnine, triethylenetetramine, tetraethylene pentamine, triethylamine, tripropylamine, anyof the butyl amines (n, iso, sec or ter), hexylamine,dimethylcyclohexylamine, dimethyl pentylamine, hydrazine, piperazine,methyl piperazine and furfurylamine.

The sensitizer may be hydrous or anhydrous, its character does notinfluence the sterilization time or effect.

The procedure used for testing the effectiveness of the varioussterilizers comprised loading two different sizes of test tubes (10 mm.ID. and 25 mm. I.D.), and somewhat larger containers with anamine-sensitized nitromethane liquid explosive. Twenty each of the threesize vessels (the two test tubes and container) were utilized. Five ofeach size were test fired over steel or aluminum witness plates. Typicaldents were 0120-0200 inch deep, indicating high order of initiation andpropagation. The sterilizing agent being tested was added to the each ofthe remaining test tubes and containers of the explosives. After fiveminutes, ten of the so-sterilized explosives of each size of the threevessels were test fired over witness plates using Du Pont No. 8 or E-83detonators for initiation.

In each instance, the lack of dent on the witness plate indicated nofiring and no detonation of the explosive, thus demonstrating theeffectiveness of the sterilizing agent. An attempt was made tore-sensitize the remaining test tubes or containers of the sterilizedexplosives by adding thereto more of the amine sensitizer. Thethusattempted re-sensitized explosives were test fired using No. 8 orE-83 detonators. In all instances, it proved impossible to re-sensitizethe explosive once it had been sterilized.

What is claimed is:

1. The improvement in the handling of a nitroparatfin liquid explosivewherein the sensitized explosive is later desensitized, said improvementcomprising:

placing the nitroparafiin in a detonable form by adding thereto an aminesensitizer to form a sensitized liquid explosive consisting essentiallyof the nitroparaffin and the amine;

incorporating in the sensitized explosive a desensitizing agent in anamount effective to render the explosive nondetonable, saiddesensitizing agent being selected from the group consisting ofpolycarbonate, diphenyl ester of carbonic acid, furaldehyde,2,5-dimethyl 2,4- hexadiene, tributoxyborine, tributylester ofphosphoric acid, tetraethylborosilicate, benzaldehyde, 1-phenyH-propanone, hexanone, succinic anhydride, maleic anhydride or acombination thereof; and

permitting the desensitizing agent to act to place the nitroparafiinexplosive in an inert, nondetonable form.

2. A process in accordance with claim 1 wherein the 10 sterilizing agentcomprises 4 to 15 weight percent of the liquid explosive.

References Cited UNITED STATES PATENTS 5/1962 Fox l4989 X 4/1964 Bost etal 14989 X

